Hypoxia

[shaggydog 0]

Does anyone know what height lack of oxygen becomes a big factor and how several jumps from 13K in one day will effect the body.

After a day at the DZ I usually feel pretty tired even though most of the day I am just bumming around. I think the adrenaline must play a part in this but I wonder if exposure to lack of oxygen would cause this too?
does everyone else find this or is it just me?

[gemini 0]

Altitude and Performance

Performance can seriously deteriorate within 15 minutes at 15.000' feet. Night vision can be impaired starting as low as 5,000'. Heavy smokers-- May experience early symptoms of hypoxia at lower altitudes.

Altitude and blood-oxygen saturation

Sea level--about 95 to 98 percent.

10,000 feet--About 90 percent; you could begin to experience some of the symptoms of blood-oxygen starvation.

14,000 feet--About 84 percent; thought, memory. and judgment processes are substantially impaired. Peripheral vision may be affected, and hands could begin to shake.

16,000 feet--About 77 percent; you may not be capable of controlling the aircraft and could even lose consciousness.

18,000 feet--loss of consciousness could occur in 15 to 30 minutes.

Above 18,000 feet--Effects of hypoxia are described in terms of time of useful consciousness, which ranges from 10 minutes at 20,000 feet to 15 seconds at 40,000 feet (see the accompanying chart).
Tlme of useful
consciousness
Altitude (ft) without oxygen

40,000 15 seconds
35.000 20 seconds
30,000 30 seconds
28,000 1 minute
26,000 2 minutes
24,000 3 minutes
22,000 6 minutes
20,000 10 minutes
15.000 Indefinite

Source: "Physiologically Tolerable Decompression Profiles for Supersonic Transport Type Certification," Office of Aviation Medicine Report AM' 70-12, S. R. Mohler, M.D., Washington, D.C.; Federal Aviation Administration, July 1970.

Blue skies,

Jim

[PhillyKev 0]

Yeah, but that's not going to effect you hours later, is it? I always figured it was the adrenaline crash that made a day of jumping so tiring.

[Tonto 1]

Also depends on your aclimitisation. For instance, if you'd just summited Kilimanjaro, at 19400ft, and then went to that altitude - you wouldn't pass out. You'd just walked there yesterday!

Our DZ is 5000ft ASL. Nationals is underway. Oxygen is available for those from the coast, as many of them just pass out as we go through 9000AGL (14AMSL) The Porter doesn't climb that fast - but manages 11 000AGL (16 AMSL) in about 12 min.

t

It's the year of the Pig.

[BlueEyedMonster 0]

Quote

Above 18,000 feet--Effects of hypoxia are described in terms of time of useful consciousness, which ranges from 10

We had a new pilot once that made a little mistake. Of course we sat in the back of the plane with big grins. I have a large lung capacity, and have never smoked. At 18.5 AGL which is about 19.5 MSL. I never felt a difference. Most of the people on the plane did though, but most smoke. So, I have to question these numbers. I most definitely was not in danger of loosing consciousness within minutes. I did not even become light headed in the 5-10 minutes I was above the 18.0 MSL mark.

[pilotdave 0]

Thats the scary thing about hypoxia. It makes you think everything is alright. Pilots are taught that when you're flying up high, if life just seems to be perfect and you're feeling great, it's time to come on down. Not being light headed does NOT mean you aren't suffering from hypoxia.

It's true that it will affect different people at different altitudes. Thats what pisses me off about that question on the B license test. It's just not accurate.

I read an article a couple years ago in some flying magazine. They hooked up a portable pulse oximeter (is that the correct terminology for the thingy that clips onto your finger and measures the oxygen in your blood?) to a pilot while flying at 9000 feet msl. The idea was to test an emergency oxygen bottle. At that altitude the oxygen in the blood would drop off to a dangerous level. Every 10 minutes or so the pilot would take a puff of oxygen and he'd be fine for a while. He couldn't feel the difference, but the instrument told him he needed the oxygen and that it worked.

Dave

[quade 3]

Fer instance . . . Oximeter

quade -
The World's Most Boring Skydiver

[Zenister 0]

Quote

Thats the scary thing about hypoxia. It makes you think everything is alright.

exactly during the Altitude chamber i went thru as part of aircrew training one of the common exercises was to write your name continually on the way 'up'

seems easy. somewhere around 17k my signature became a wobbly line that bore no resemblence to any language..i had no idea until the guy next to me pointed it out before he passed out laughing so hard and had to have his mask put on...

by the time you notice symptoms its already to late...

____________________________________
Those who fail to learn from the past are simply Doomed.

[skycat 0]

I think a better question is "Are you suffering from altitude sickness?". The effects of hypoxia tend to go away as you re-enter more oxygenated air, while altitude sickness can last hours.

Here is a link to learn more about altitude sickness.http://www.princeton.edu/~oa/safety/altitude.html

btw...you aren't at altitude long enough to get altitude sickness, although it is possible to get some of the symptoms if you are doing go arounds long enough. Just drink lots and lots of water during the day and listen to your body, if you have a headache and feel a little queezy, don't get on the next load.

Fly it like you stole it!

[Tonto 1]

"..i had no idea until the guy next to me pointed it out before he passed out laughing so hard and had to have his mask put on..."

5 of us were in a DC 3, 5 miles out to sea off the coast of Maputo, Mozambique. 3 were stunt doubles for a film shoot, 1 camera person, and me co-ordinating with the chase plane and the chopper on a sandbar which would pick us up off an "island" about 150 sq feet big. (That was turned into an iceberg in post production)

We got put on hold at 12 000 in the late afternoon as all the international flights were coming in. about 45 min later, Ed said something, and we all just cracked up, rolling in the isle. He looked like a fly.
What was odd was that he was in "wardrobe" and had been wearing that freefly suit for days... but NOW... Now that was funny.

So I recognised the symptoms. I went up front, and both pilots (who I'm sure were older than the DC3), had their masks on. I asked them to take us down to 9000 for a while. All normal after that. Great visuals on that dive...
t

It's the year of the Pig.

[phonics1981 0]

But will this affect how you feel all day? In the first post it was mentioned that he was tired all day and wanted to know if this was anything to do with hypoxia.

------------------------------------------------------
"Ive given up on sigs cos I make a mess of them!"
------------------------------------------------------

[Tonto 1]

I don't think so. Hypoxia is simply not enough Oxygen for us to function properly.

In longer term exposure, such as climbing, Hape and Hace (High altitude Pulminary/Cerebril Edema) become an issue. In all cases decent is the best cure, and symptoms abate almost immediatly, although there is some "hangover" effect there.

Some people are simply not "jump fit" I see some very athletic people completely shattered after ten or twelve dives in a day. If you're used to that - it's nothing but fun!

t

It's the year of the Pig.

[mark135 0]

The thread seems focused on hypoxia, which is fine, but I think the auther is suffering from the adreneline crash. I know I crash hard and sleep on the way home. I usually do 8-10 jumps a day between tandem vids and tandem master and while it isnt that much physical work I am simply beat on my ass.

_______________


"It seemed like a good idea at the time"

[Harksaw 0]

I was wondering how, as gemini said, you can go unconcious at 40,000 feet in 15 seconds, when a person could hold their breath for that long (and get NO oxygen) without passing out?

__________________________________________________
I started skydiving for the money and the chicks. Oh, wait.

[Luv2Fall 0]

I, too, think that "adreneline crash" plays a key factor here.

[phonics1981 0]

Quote

I was wondering how, as gemini said, you can go unconcious at 40,000 feet in 15 seconds, when a person could hold their breath for that long (and get NO oxygen) without passing out?

I am guessing that for to go unconcious at 40000 in 15 seconds you would have to be breathing. So for each breath you take you are getting no where near enough oxygen in the body and you then breathe out, getting rid of the very little oxygen your body took in during the last breath. If you took a breath at 0' then (somehow!) got to 40k in a second. You could still survive on the breath for as long as you could on the ground.

Hope you get what im saying, I have a complicated way of describing things

------------------------------------------------------
"Ive given up on sigs cos I make a mess of them!"
------------------------------------------------------

[pilotdave 0]

Just a guess here... when you're holding your breath, oxygen keeps getting absorbed into your blood until there's none left in the air in your lungs. But when you're breathing at 40,000 feet your lungs are never getting enough oxygen into your blood. How long would it take to pass out if you breathed out before holding your breath? Well, it's still probably more than 15 seconds but I'm guessing we arent capable of exhaling all the oxygen in our lungs.

Dave

[Harksaw 0]

I've been thinking about it, and maybe the reason you only have 15 seconds of conciousness is not only because of the hypoxia but the low air pressure?

__________________________________________________
I started skydiving for the money and the chicks. Oh, wait.

[PhillyKev 0]

Quote

I was wondering how, as gemini said, you can go unconcious at 40,000 feet in 15 seconds, when a person could hold their breath for that long (and get NO oxygen) without passing out?

Because they're holding their breath with air that has more O2 in it in the first place. If you go to 40k feet, take off your O2, then take a breath, and hold it, you'll need O2 a lot faster than if you breathed in through your mask and hold it.

[michaelmullins 77]

The charts that you are looking at refer to a worst case scenario of an explosive decompression at 40,000'. That is, you have a "normal" pressurized cabin altitude of approx. 8,000' and then a door blows off the aircraft increasing the cabin altitude to 40,000' virtually instantaneously. The air in your lungs is literally sucked out of your body and there is nothing you can do to prevent it.

Also, at altitudes above 40,000' you may not be able to "suck" enough oxygen into your lungs. The oxygen regulators on the masks certified for these altitudes will provide "pressure breathing" in that they will force oxygen into your lungs. When you resist the flow you will stop inhaling oxygen, when you relax the mask forces oxygen into you.

If you are already breathing oxygen through a mask at 40,000' and then take your mask off, you will "probably" exceed the values in the table-- but don't count on it!

Mike Mullins

[Beerlight 0]

Quote

I've been thinking about it, and maybe the reason you only have 15 seconds of conciousness is not only because of the hypoxia but the low air pressure?

This is a good thread. Anyone ever heard of the Law of Gaseous Diffusion? At 40K the partial pressure of oxygen in your system is higher than the atmospheric (ambient) pressure. (Gas) loves to travel from a higher pressure to a lower pressure. It's a gradient thing.......Your body literally gives up oxygen to the environment.

Another note, ever check your pulse while your above 10K? I can bet for most people, it will be on the high side. Hmmmm. Kinda like exercise?? So, yes the tired feeling is from that and possible from the adrenaline thing........

[skycat 0]

Quote

Another note, ever check your pulse while your above 10K? I can bet for most people, it will be on the high side. Hmmmm. Kinda like exercise?? So, yes the tired feeling is from that and possible from the adrenaline thing........

I think everyone should hike a 14'er, really shows you how your body reacts to exercise at high altitudes for long periods of time.

Yeah, I know you could go to a high alti chamber.....but what fun is there in that.

Fly it like you stole it!

[FrogNog 1]

Quote

Does anyone know what height lack of oxygen becomes a big factor and how several jumps from 13K in one day will effect the body.

After a day at the DZ I usually feel pretty tired even though most of the day I am just bumming around. I think the adrenaline must play a part in this but I wonder if exposure to lack of oxygen would cause this too?
does everyone else find this or is it just me?

I'm surprised nobody else has answered this yet - I know some dumper jumpers know the answer. When the air is thinner, your entire body has to work harder, even just sitting still. This tires you out faster. Add in some packing, temperature changes, wearing a heavy rig and being cramped up periodically, and riding the adrenaline (even if you're used to it), and someone could get plum tuckered out.

-=-=-=-=-
Pull.

[CanuckInUSA 0]

Add in a lack of sleep or a little alcohol poisioning from the night before and you've got yourself a doozy. As someone who jumps in CO, I think I can tell you that while we think we get used to it (we jump at 17500 MSL), you don't really get used to it. It effects us all, even those of us who go higher than most of you on a regular basis.

Try not to worry about the things you have no control over

[Beerlight 0]

Quote

I was wondering how, as gemini said, you can go unconcious at 40,000 feet in 15 seconds, when a person could hold their breath for that long (and get NO oxygen) without passing out?

Anytime any of you guys wish to go through an altitude chamber course, I teach one here at NASA in Houston, TX. Price: FREE

And to answer the 40,000 feet, I can hold my breathe theory? Not happening......

A. You have approx. 14 seconds of surplus oxygen in your circulatory system. (I would luv to meet the guy who figured that out, but anyways, that's what we teach). Some people will say, well I can hold my breath for a minute at sea level, so I can do that at altitude, right?

-- Reason why you can't hold your breath at that altitude? At 40K, your oxygen partial pressure in your blood will be extremely low( if your not using supplemental oxygen under pressure), and your blood hemoglobin is actually "giving up" it's oxygen back to the lungs and you are exhaling it.......ie. it's called "reverse diffusion gradient"

And YES, going to altitude severals times in a day WILL make you fatiqued due to each hypoxia cycle your body is undertaking during the day. Adrenaline "let-down" is also a factor......

This response was directed at no one in particular..

Buck Buchanan
Aerospace Physiologist
NASA, Johnson Space Center
Houston, TX